1. Field of the Invention
This invention relates to an ac power supply unit, more particularly to a highly efficient ac power supply unit.
2. Description of the Related Art
A conventional ac power supply unit usually includes a high power transformer for an inverter portion of the power supply unit. The high power transformer reduces the efficiency of the ac power supply unit since it consumes a large amount of power. Furthermore, only a 110 V ac voltage output or a 220 V ac voltage output is available in the conventional ac power supply unit, thereby limiting the applicability thereof.